(Newser)
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President Obama will meet with Vladimir Putin at the G20 summit in Mexico today, in what promises to be a contentious tête-à-tête, the AFP reports. It will be Obama's first meeting with Putin since his re-ascendance to Russia's presidency, and the leaders don't seem nearly as simpatico as Obama and Dmitry Medvedev were; Obama waited days to congratulate Putin on his election victory, Politico points out, and Putin snubbed the G8 conference. There are substantive policy disputes as well, particularly over Syria.

Greece is widely expected to dominate discussion at the summit. Leaders were generally upbeat in the wake of Greece's vote, but the issue is still contentious. David Cameron today urged Greece's parties to "get on with it and help form a government" to avoid a eurozone exit, the Telegraph reports. Obama will try to convince European leaders to do more to encourage growth. He will also have a meeting with Hu Jintao, at which Syria is expected to be a major topic of conversation, and with Felipe Calderon—the final such meeting before Mexico's presidential election. (Read more Greece stories.)

Huge "true" leadership opportunity for both of these men. Will they use this as a "defining moment" that not only their respective countries, but indeed the global community, appear to both be ready for and indeed need?